he took us through an elementary school that officials didn't want us to name. showed us what to do if that nightmare unfolds. >> exits are obviously key, right? >> yes. >> find the nearest one. >> absolutely, absolutely. and it's important to be familiar with the building. that's why, again, we encourage just little things. a building familiarization, just walking the outside of the building so you know if you believe this particular door if it comes to a creek or a parking lot or a busy intersection. >> reporter: adults and students, he says, have to have that exit awareness. but if you're stuck inside, michael blow says while bathrooms may be a tempting place to hide at first, not a good idea. as you can see, a very confined space and usually no way out. courtyards, he says, are equally tempting but also not the best places because they're often enclosed. >> michael, if there's a classroom, there's a gunman out there, we've heard shots, don't know where he is. what do we do? we lock, turn lights off, close windows? >> well, certainly there are a host of thing